The partner of the Guardian journalist who has written a series of stories revealing mass surveillance programmes by the US National Security Agency was held for almost nine hours on Sunday by UK authorities as he passed through London's Heathrow airport on his way home to Rio de Janeiro.

David Miranda, who lives with Glenn Greenwald, was returning from a trip to Berlin when he was stopped by officers at 8.05am and informed that he was to be questioned under schedule 7 of the Terrorism Act 2000. The controversial law, which applies only at airports, ports and border areas, allows officers to stop, search, question and detain individuals.

Miranda also had all his equipment confiscated. He has done nothing wrong - there's no charges, no criminal suspicion, nothing at all. His only crime is being the partner of a famous journalist who, among other things, is one of the driving forces behind shining a light on the NSA's mass surveillance.